This invention relates to methods for performing a medical procedure, especially a procedure during which it is necessary to adjust the beating of the heart. More particularly, this invention relates to methods and systems of stimulating a nerve in order to modify the beating of a heart to allow a medical procedure to be performed or for blood flow to be controlled.
The current leading cause of death in the United States is coronary artery disease in which the coronary arteries are blocked by atherosclerotic plaques or deposits of fat. The typical treatment to relieve a partially or fully blocked coronary artery is coronary artery bypass graph (CABG) surgery.
CABG surgery, also known as xe2x80x9cheart bypassxe2x80x9d surgery, generally entails using a graph to bypass the coronary obstruction. The procedure is generally lengthy, traumatic and subject to patient risks. Among the risk factors involved is the use of a cardiopulmonary bypass (CPB) circuit, also known as a xe2x80x9cheart-lung machine,xe2x80x9d to pump blood and oxygenate the blood so that the patient""s heart may be stopped during the surgery.
Conventional CABG procedures are typically conducted on a stopped heart while the patient is on a (CPB) circuit. A stopped heart and a CPB circuit enables a surgeon to work in a bloodless, still operative field. However, there are a number of problems associated with CABG procedures performed while on CPB including the initiation of a systemic inflammatory response due to interactions of blood elements with the artificial material surfaces of the CPB circuit and global myocardial ischemia due to cardioplegic cardiac arrest. For these reasons, avoiding the use of CPB or cardioplegic cardiac arrest may help minimize post-operative complications.
One method, as disclosed in U.S. Pat. No. 5,651,378 to inventors Matheny and Taylor and in U.S. Pat. No. 5,913,876 to inventors Taylor et al., for facilitating coronary bypass surgery on a beating heart and thereby avoid the use of CPB and cardioplegic cardiac arrest includes stimulating the vagal nerve electrically in order to temporarily stop or substantially reduce the beating of the heart. This may be followed by pacing the heart to start its beating.
Another method, as disclosed in two published PCT applications, WO 99/09971 and WO 99/09973, both to inventor Puskas, involves stopping the beating of the heart during coronary bypass surgery using electrical stimulation of the vagal nerve in combination with administration of drugs. Another method, as disclosed in U.S. Pat. No. 6,060,454 to inventor Duhaylongsod, involves stopping the beating of the heart during coronary bypass surgery via the local delivery of drugs to the heart.
Although it is desirable to stop the heart for a period of time in order to allow the surgeon to accomplish a required task without interference from heart movement, i.e. a motionless operative field, it is undesirable to have the heart stopped for too long a period of time since the body needs, among other things, a constant supply of oxygen. In fact, it is particularly important to maintain sufficient blood flow, and therefore oxygen flow, to the brain. Stopping the heart for prolonged periods of time may cause damage to the patient.
It is thus important to be able to precisely control and coordinate the amount and duration of stimulation to the vagal nerve and the heart. One type of electrode arrangement that allows such precise control is an electrode tube which is suitable for insertion into a patient""s trachea or esophagus. This arrangement provides a configuration of electrodes which can not only stimulate a variety of nerve fibers but may also be configured to stimulate the patient""s heart, ventilate the patient""s lungs and/or control pain during stimulation. This electrode arrangement also allows for sensing or monitoring of various physiological processes.
It would be desirable therefore to provide a method for controllably stopping or slowing the heart intermittently for diagnostic and therapeutic purposes.
Additionally, it would be desirable to provide a method for controllably stopping or slowing the heart intermittently in order to control blood flow.
Additionally, it would be desirable to provide a method for controllably stopping or slowing the heart intermittently in order to perform a medical procedure on the heart or another organ.
Additionally, it would be desirable to provide a means for coordinating stimulation of the heart and other body components.
Additionally, it would be desirable to provide a means for evaluating the stimulation output from a variety of electrodes to determine the best stimulation configuration.
One aspect of the present invention provides a method for evaluating stimulation during a medical procedure. A site is stimulated with a first electrode arrangement. The stimulation at the site is then evaluated to provide a first stimulation value. The first electrode arrangement may comprise one or more electrodes such as nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, tape-type electrodes, suction-type electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes, probe electrodes, cardiac stimulation, electrode, pacing electrodes and epicardial electrodes.
The method may also involve stimulating the site with a subsequent electrode arrangement and evaluating stimulation to provide a subsequent stimulation value. The first stimulation and subsequent stimulation values may be compared to determine a best stimulation value and stimulation may. be continued with the electrode arrangement associated with the best stimulation value. The subsequent electrode arrangement may comprise one or more electrodes such as nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, tape-type electrodes, suction-type electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes, probe electrodes, cardiac stimulation electrode, pacing electrodes and epicardial electrodes.
Another aspect of the present invention provides a method of performing a medical procedure. A nerve is stimulated with a first electrode arrangement to adjust the beating of a heart to a first condition. Stimulation is evaluated from the first electrode arrangement to provide a first stimulation value. The nerve is then stimulated with a subsequent electrode arrangement and stimulation is evalulated from the subsequent electrode arrangement to provide a subsequent stimulation value. A desired electrode arrangement is selected based on the first stimulation value and the subsequent stimulation value and the nerve is stimulated with the desired electrode arrangement. The first and the subsequent electrode arrangements may comprise one or more electrodes such as nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, tape-type electrodes, suction-type electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes, probe electrodes, cardiac stimulation electrode, pacing electrodes and epicardial electrodes.
The medical procedure may be performed on an organ. Stimulation of the nerve may then be reduced or stopped to adjust the beating of a heart to a second condition. The nerve may then be stimulated a subsequent time to re-adjust the beating of the heart to the first condition and the medical procedure then continued. The nerve may be stimulated using transvascular stimulation or endophageal stimulation. The first condition may be a stopped or slowed condition. The second condition may be a beating condition. The heart may be stimulated to adjust the beating of the heart to the second condition. For example, the heart may be stimulated with a first cardiac electrode arrangement to adjust the beating of the heart to the second condition. Stimulation from the first cardiac electrode arrangement may be evaluated to provide a first cardiac stimulation value. The heart may then be stimulated with a subsequent cardiac electrode arrangement and stimulation from this arrangement may be evaluated to provide a subsequent cardiac stimulation value. A desired cardiac electrode arrangement may then be selected based on the first cardiac stimulation value and the subsequent cardiac stimulation value and the heart may be stimulated with the desired cardiac electrode arrangement. The first and subsequent cardiac electrode arrangements may be one or more electrodes such as cardiac stimulation electrodes, clip electrodes, needle electrodes, probe electrodes, pacing electrodes, epicardial electrodes, patch electrodes, intravascular electrodes, balloon-type electrodes, basket-type electrodes, tape-type electrodes, umbrella-type electrodes, suction-type electrodes,endotracheal electrodes, endoesophageal electrodes, transcutaneous electrodes, intracutaneous electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes and cuff electrodes.
The method may also include delivering a drug such as a beta-blocker, a cholinergic agent, a cholinesterase inhibitor, a calcium channel blocker, a sodium channel blocker, a potassium channel agent, adenosine, an adenosine receptor agonist, an adenosine deaminase inhibitor, dipyridamole, a monoamine oxidase inhibitor, digoxin, digitalis, lignocaine, a bradykinin agent, a serotoninergic agonist, an antiarrythmic agent, a cardiac glycoside, a local anesthetic, atropine, a calcium solution, an agent that promotes heart rate, an agent that promotes heart contractions, dopamine, a catecholamine, an inotrope glucagon, a hormone, forskolin, epinephrine, norepinephrine, thyroid hormone, a phosphodiesterase inhibitor, prostacyclin, prostaglandin and a methylxanthine during the medical procedure. The drug may be naturally occurring or chemically synthesized.
The nerve may be a nerve such as a vagal nerve, a carotid sinus nerve, a fat pad.
The medical procedure may be surgical procedures, non-surgical procedures, endoscopic procedures, fluoroscopic procedures, stent delivery procedures, aortic aneurysm repairs, cranial aneurysm repairs, delivery of drugs, delivery of biological agents, cardiac surgery with cardiopulmonary bypass circuits, cardiac surgery without cardiopulmonary bypass circuits, brain surgery, cardiograms, heart valve repair, heart valve replacement, MAZE procedures, transmyocardial revascularization, CABG procedures, beating heart surgery, vascular surgery, neurosurgery, electrophysiology procedures, diagnostic ablation of arrhythmias, therapeutic ablation of arrhythmias, endovascular procedures, treatment of injuries to the liver, treatment of the spleen, treatment of the heart, treatment of the lungs, treatment of major blood vessels, non-invasive procedures, invasive procedures, and port-access procedures.
Another aspect of the present invention provides a device for performing a medical procedure. The device includes a first electrode arrangement operatively arranged on a stimulation tube and a second electrode arrangement operatively arranged on a stimulation collar. The first and the second electrode arrangements may comprise one or more electrodes such as nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, tape-type electrodes, suction-type electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes, probe electrodes, cardiac stimulation electrode, pacing electrodes and epicardial electrodes. The device may also include a processor for evaluating stimulation from a set of electrodes, the pair of electrodes comprising at least one electrode from the stimulation tube and at least one electrode from the stimulation collar.
Another aspect of the present invention provides a system for performing a medical procedure. The system includes a first electrode arrangement operatively arranged on a stimulation tube, a second electrode arrangement operatively arranged on a stimulation collar, a processor for evaluating stimulation from a set of electrodes, the pair of electrodes comprising at least one electrode from the stimulation tube and at least one electrode from the stimulation collar and a controller for controlling stimulation from the set of electrodes. The first and the second electrode arrangements may comprise one or more electrodes such as nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, tape-type electrodes, suction-type electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes, probe electrodes, cardiac stimulation electrode, pacing electrodes and epicardial electrodes.
The system may also include drug delivery means such as a spray, a cream, an ointment, a medicament, a pill, a patch, a catheter, a cannula, a needle and syringe, a pump, and an iontophoretic drug delivery device for delivering drugs during the medical procedure.
Another aspect of the present invention provides a method of performing heart surgery. A nerve is transvenously stimulated with a first electrode arrangement to reduce the beating of a heart. Stimulation from the first electrode arrangement is evaluated to provide a first stimulation value. The nerve is then stimulated with a subsequent electrode arrangement and the stimulation is evaluated to provide a subsequent stimulation value. A desired electrode arrangement is selected based on the first stimulation value and the subsequent stimulation value and the nerve is stimulated with the desired electrode arrangement. The heart is then operated upon. Stimulation of the nerve is then stopped and the heart is stimulated to cause beating of the heart. The nerve is then re-stimulated to re-inhibit beating of the heart and the surgery is continued. The heart may also be stimulated with a first cardiac electrode arrangement to adjust the beating of the heart to the second condition. Stimulation from the first cardiac electrode arrangement may be evaluated to provide a first cardiac stimulation value. The heart may then be stimulated with a subsequent-cardiac electrode arrangement and stimulation from this arrangement may be evaluated to provide a subsequent cardiac stimulation value. A desired cardiac electrode arrangement may then be selected based on the first cardiac stimulation value and the subsequent cardiac stimulation value and the heart may be stimulated with the desired cardiac electrode arrangement.
The foregoing, and other, features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims in equivalence thereof.